The Department of Veterans Affairs has embraced the patient-centered medical home, termed the Patient-Aligned Care Team (PACT) in VA, an approach that promises care that is comprehensive, patient- centered, team-based, focused on coordination and communication, and able to sustain a relationship that continues over time. For patients who are homeless or exiting homelessness, these ideals are often not met. Despite significant efforts to develop patient-centered medical homes for people who are homeless, little is known about the particular aspects service design delivery that create valuable, enduring primary care experiences for patients. Since 2012, VA has ambitiously piloted homeless-tailored primary care service design through Homeless PACTs (HPACTs, n=60). This has created a natural experiment that invites two questions important not just to VA but to non-VA agencies seeking to promote viable medical homes for socially-vulnerable populations. First, do VA's homeless-tailored primary care programs offer a substantively superior patient experience? Second, what particular organizational features actually matter? This proposal prioritizes homeless patients' experience of primary care as the proximal indicator of successful engagement in primary care. Patient experience surveys seek an experiential report of how well aspects of care delivery (access, coordination, etc.) map to what patients and experts consider ideal. In prior VA-funded research, we asked patients and providers about their aspirations for primary care of the homeless. From this we developed a psychometrically valid patient experience survey (Primary Care Quality-Homeless, PCQ-H), which has been used in homeless health care programs across the country. This study will combine patient surveys from homeless-experienced (currently and previously homeless) veterans (n=6,181) and organizational assessment among a sample of HPACTs to advance two aims: Aim 1: Compare the primary care experience (i.e. PCQ-H scores) for homeless-experienced patients obtaining primary care in HPACTs to patients receiving primary care in mainstream PACT clinics operated by the same VA Medical Center. Aim 2: Characterize those features of HPACT service design that are most strongly associated with a superior patient experience (i.e. better PCQ-H scores). This Aim will be advanced sequentially through (a) adaptation of an organizational assessment tool specific to homeless-tailored primary care for use in this project; (b) conducting that assessment through surveys of HPACT directors to identify the presence or absence of potentially relevant HPACT service features; (c) analysis to compare PCQ-H scores for HPACTs that have versus those that lack each potentially relevant HPACT service feature. Evidence from this study will help to guide the future of primary care delivery for homeless and formerly homeless patients within VA, and in non-VA Federally Qualified Health Centers. Additionally, it may help to foster a primary care culture that holds itself accountable, first and foremost, to the unique contextual needs of patients as they leave homelessness behind.